Lighting system with a daily rhythm and dim light dynamics

ABSTRACT

The invention provides a lighting system ( 100 ) comprising a first lighting element ( 10 ) and a control unit ( 50 ), wherein: a) the first lighting element ( 10 ) is configured to provide first lighting element light ( 11 ) with controllable lighting intensity, wherein the first lighting intensity can be selected from a plurality of values in the range of 0-I, with I being a predetermined first lighting element maximum intensity; b) the control unit ( 50 ) is configured to maintain a first lighting element intensity, during a first predetermined period at an intensity value larger than zero when a general lighting intensity is below a predetermined first threshold level; c) the control unit ( 50 ) is further configured to maintain the first lighting element intensity during a second predetermined period at an intensity value a*y*I when the general lighting intensity level is y*I, y being the factor the general lighting intensity is below I, with 0&lt;y&lt;1, the parameter a being a predetermined lighting setting with 0&lt;a≦1/y; and d) the lighting system is further configured to provide during a third predetermined period first lighting element light ( 11 ) with a dynamic property selected from the group of a moving or changing light pattern, a color change, and an intensity change.

CROSS-REFERENCE TO PRIOR APPLICATIONS

This application is the U.S. National Phase application under 35 U.S.C.§371 of International Application No. PCT/EP2014/069744, filed on Sep.17, 2014, which claims the benefit of European Patent Application No.13185513.2, filed on Sep. 23, 2013. These applications are herebyincorporated by reference herein.

FIELD OF THE INVENTION

The invention relates to a lighting system and a method for controllinglighting in a room, for instance with such lighting system. Theinvention also relates to a computer program product, when run acomputer, being configured to control a lighting system according tosuch method.

BACKGROUND OF THE INVENTION

The generation of light cycles is known in the art. U.S. Pat. No.5,589,741, for instance, describes a naturalistic illumination systemfor a user at a location having a light source for providingillumination of variable intensity above a non-zero value to the userlocation. A computer produces a variable signal to control a cycle ofvariable intensity illumination level output of the light source tocorrespond to the progressive variation in light level intensity above anon-zero value over a selected time of day period at a geographicallocation as selected from a computer input device. The variable signalis produced on a daily basis to produce the variable intensityillumination cycle for the same period of time in a manner toprogressively shift the time of the start of the production of thevariable intensity illumination cycle for the period of time each dayover a period of successive days relative to the normal time of start ofthe production of the variable intensity illumination cycle during theperiod of successive days at the selected geographical location. Thevariable signal also can be produced to shift the time of start of thevariable intensity illumination cycle for each day and to cause a dawnto dusk or dusk to dawn transition of the illumination cycle transition.

SUMMARY OF THE INVENTION

Light coming in the eye and falling upon a third photoreceptor regulatesthe biological clock in mammals. The biological clock has a daily rhythmwhich can be influenced by light. The biological clock regulates oursleep-wake rhythm and impacts well-being. Moreover, dynamic lighteffects can play an important role in the well-being and sleep-wakeregulation of people. The room ambience impacts the stress levels andaffective state of the person living in that room. This can have apositive influence on the sleep-wake cycle, when a person becomes lessstressed and more relaxed in a pleasant atmosphere while falling asleepor returning to sleep after a nocturnal awakening. Dynamics lighteffects can be used to activate or unwind people on different moments ofthe day.

The sleep-inducing nocturnal ‘hormone of darkness’ melatonin is oftenused as a marker for the biological clock and the sleep-wake rhythm ofan individual. Consolidated sleep is only possible during melatoninsecretion. Light at night is known to enhance alertness but alsosuppresses the melatonin secretion, compromising sleep. Melatonin isknown to have radical scavenging properties and seems to be involved inprotection against tumorgenesis and tumor growth, another reason whymelatonin suppression is not desired. For optimal sleep, (near) darknessis the most favorable condition to sleep in.

Darkness or dim light can make people (like demented elderly, babies andchildren) feel uncomfortable, and does not always provide the rightambience to unwind and relax while falling asleep, or when trying toreturn to sleep. Darkness or dim light conditions are needed for goodand consolidated sleep, but do not always provide an attractiveatmosphere/ambience to fall asleep, or quickly return to sleep afternocturnal awakenings. In many care environments like elderly care-homespediatric wards, geriatric wards or NICU (neonatal intensive care units)facilities, the sleep of the individuals cared for is not optimal. Thecurrent general lighting systems in care institutions do not allow forlight settings that promote a rapid sleep onset.

Hence, it is an aspect of the invention to provide an alternativelighting system and/or an alternative lighting method (or method forcontrolling lighting in a room), which preferably further at leastpartly obviate one or more of above-described drawbacks. It is furtheran aspect of the invention to provide an alternative computer programproduct that may be used to execute the method (when run on a computer).

It surprisingly appears that the use of dynamic (dim) light effects mayhelp creating a more pleasant atmosphere that facilitates a rapid sleeponset, or a rapid return to sleep after a nocturnal awakening. However,dynamic dim light effects are never provided within general lightingsystems in e.g. hospital patient rooms, neonatal intensive care units,elderly care facilities or hotel-/bed-rooms.

Hence, in a first aspect the invention provides a lighting system(“system”) comprising a first lighting element (herein also indicated as“night light” or “dim light”) and a control unit, wherein

a) the first lighting element is configured to provide first lightingelement light with controllable (lighting element) intensity, especiallycontrollable (lighting element) luminous flux, wherein the lightingelement luminous flux can especially be selected from a plurality ofvalues in the range of 0-Φ, with Φ being a predetermined first lightingelement maximum luminous flux (functionality a);b) the control unit is especially configured to maintain a firstlighting element illuminance at a first position (p1) within a firstdistance (d1) from the lighting element, with the first distanceespecially selected from the range of 0<d1≦15 m (see also below), duringa first predetermined period at a specific (variable) intensity,especially at an illuminance value larger than zero, when a generallighting illuminance level at said first position (p1) is below apredetermined first threshold level (functionality b);c) the control unit is further especially configured to maintain thefirst lighting element illuminance at said first position (p1) during asecond predetermined period at an illuminance value a*y*E when thegeneral lighting illuminance level at said first position (p1) is y*E, ybeing the factor the general lighting illuminance is below E, with0<y≦1, parameter a being a predetermined lighting setting with 0<a≦1/y,and with E being the predetermined first lighting element maximumilluminance at said first position (p1) (functionality c); andd) the lighting system is further especially configured to provideduring a third predetermined period first lighting element light with adynamic property, especially selected from the group of a moving or achanging of a light pattern, a color change, and an intensity change,wherein especially during the third period a plurality of times one ormore of the following sequentially takes place (i) the moving of thelight pattern, (ii) the changing of the light pattern), (iii) the colorchange of the first lighting element light, and (iv) the intensitychange of the first lighting element light (functionality d).

In yet a (more general) aspect the invention provides a lighting systemcomprising a first lighting element and a control unit for controllingthe first lighting element to provide a first lighting element light,wherein the lighting system is configured to (a) adapt during a (first)predetermined period the first lighting element light to a generallighting level, and (b) provide during a further predetermined periodthe first lighting element light further comprises a dynamic propertyselected from the group of moving or changing a light pattern, changinga color, and changing an intensity of said first lighting element light.Especially, such lighting system may be configured to (b) adapt during asecond predetermined period the first lighting element light to a dimmedlighting level wherein the dimmed lighting level further comprises adynamic property selected from the group of moving or changing a lightpattern, changing a color, and changing an intensity of said firstlighting element light. The (first) predetermined period and the further(or second) predetermined period may in an embodiment be two differentperiods or may in another embodiment be partially or entirelyoverlapping periods. For instance, in the former embodiment first firstlighting light may be provided of which the intensity may be adapted toa general lighting level and during a second period, the dynamiclighting may be provided, of which the intensity may optionallyespecially (also) be adapted to a general lighting level. Hence, in thisway for instance dimmed light with a dynamic effect may be provided. Forinstance, the (first) predetermined period may be a period during theday, and the further predetermined period may be a nocturnal period.Further, especially during said further (or second) period a pluralityof times one or more of the following sequentially may take place (i)the moving of the light pattern, (ii) the changing of the lightpattern), (iii) the color change of the first lighting element light,and (iv) the intensity change of the first lighting element light.Especially, the dynamic property includes one or more of a color changeand a light pattern change.

With such lighting system(s), it is possible to provide light (“firstlighting element light”) during periods of sleep, or during a period aperson may desire to fall asleep or should fall asleep, or during aperiod a person desires to wake up or should awake, which may fit wellto the specific period. The lighting system may adapt the lightintensity of the first lighting element (and optionally other lightingelements when available in the lighting system) to a general lighting(intensity level) that is available, and even to the varying intensity(level) of such general lighting. Further, the lighting system mayprovide dynamics in the lighting (i.e. first lighting element light)which may not be too fast and which may not be too slow, especiallyduring the period a person may desire to fall asleep or should fallasleep and/or during a period a person desires to sleep or should sleep.Hence, also during a nocturnal awaking such dynamic lighting may beprovided, which may assist in falling asleep again.

The lighting system may use dynamic dim light during part of its,preferably 24 hr., rhythm. The dynamic dim light effects yields specificemotional and/or health and well-being benefits. They shape an ambience(for instance a starry sky) in a patient (bed) room or elderly (bed)room or baby (bed) room that makes the person in the bed more relaxedand less stressed, thus having a positive influence on the time it takesto fall asleep. The dynamics and spectral composition (such as bluedeprived), and (low) intensity of the dim light condition is chosen notto suppress nocturnal melatonin secretion.

This invention may especially include a method (see also below) for thecontrolled lighting of an area by means of a lighting system. Forinstance, the method may comprise a predetermined time program thatprovides (1) general lighting during a predetermined general lightingperiod, (2) dynamic dim light effects (with first lighting elementlight) during a dim light period where the luminance or illuminancelevels are low while some of the (il)luminated areas are dynamic intheir location, intensity and/or spectral composition, with the dynamiccycle time being in the interval of especially 1 second-6 hours,especially 1 second to 3 hours, even more especially 1 second to 30minutes, like 1-420 seconds, such as especially 1-120 seconds, such asat least 10 seconds, like at least 5 minutes.

Especially, the entire time program may run for more than 6 hrs.,preferably 24 hrs., or especially a plurality of days (of 24 hours).Such entire program may address the herein indicated predeterminedperiods, like especially the first, second and third periods.

Further, the method (and lighting system) may include a control unitconfigured to control the lighting system according to the predeterminedtime program. Further, especially the dynamic light effects (of thefirst lighting element light) are either created via projection ofmoving images or with patterns of light dots on a pixelated light exitwindow, such as in a specific embodiment a ceiling luminaire.Optionally, more than one kind of nocturnal dynamic dim light lighteffect can be envisioned for different purposes/times, especially one ormore of (a) falling asleep, (b) nocturnal awakenings, and (c) waking up.Alternatively or additionally, the system can be connected to biofeedback signals. Further, also alternatively or additionally inembodiments the user can personalize the dynamic light effects via auser interface. Hence, amongst others the invention may include alighting system with a daily rhythm that includes a period with specialdim (and/or bright) light dynamics, amongst others dedicated to fallasleep (and/or wake-up) more easily.

As indicated above, the lighting system at least comprises a firstlighting element. The lighting element comprises one or more lightsources that provide light. Further, the first lighting elementcomprises a light exit window. A user may perceive light from the firstlighting element escaping from such light exit window. Hence, the firstlighting element light is especially light downstream from the lightexit window. This light may for instance be perceived directly, orindirectly. For instance, with respect to the latter embodiment, thefirst lighting element may be configured to project (during the thirdperiod) a light pattern on a ceiling.

The terms “upstream” and “downstream” relate to an arrangement of itemsor features relative to the propagation of the light from a lightgenerating means (here the especially the first lighting element),wherein relative to a first position within a beam of light from thelight generating means, a second position in the beam of light closer tothe light generating means is “upstream”, and a third position withinthe beam of light further away from the light generating means is“downstream”. The term “first position” may also refer to a plurality offirst positions, such as e.g. at a ceiling and at a wall. Hence, dynamiceffects may for instance be displayed at two or more positions in aroom. Optionally, the properties of the first lighting element light (asdescribed herein) at two or more first positions may be independentlycontrollable. For instance, the dynamic effects may differ from firstposition to other first position.

Especially, the first lighting element comprises the ability to tune theintensity of the first lighting element light. Not only off (zerointensity) and maximum intensity (indicated with “E”, see also below),but also values in between can be chosen. Hence, a plurality ofintensities can be chosen, such as in addition to zero intensity andmaximum intensity, also at least 4, even more especially at least 10different intensities. Hence, the first lighting element has acontrollable light intensity. The control unit is configured to controlthis intensity. Especially, the first lighting element has a maximumluminous flux of 10,000 lumens, even more especially a maximum luminousflux of 5,000 lumens. Further, the lighting element illuminance can(thus) be selected from a plurality of values in the range of 0-Φ, withΦ being a predetermined maximum first lighting element illuminance. Thecontrollable intensity is herein also indicated as functionality a).

Further, the control unit may especially be configured to maintain thefirst lighting element illuminance at a first position (p1) within afirst distance (d1) from the lighting element, with the first distanceespecially selected from the range of 0<d1≦15 m. The lighting elementmay be designed in such a way that the illuminance at 1 meter (d1=1 m)is at maximum 50 lux. This may for instance be of interest forapplication on a night stand or pedestal cupboard. The luminous flux isthe total amount of light from a light source defined towards thesensitivity curve of the human eye. Luminous flux has as unit Lumen(Lm). The illuminance is the luminous flux that hits an area divided bythe size of the area. The illuminance is indicated with Lux (lx) and canbe defined as Φ/A. The illuminance may thus decrease with increasingdistance from the source of light. The luminous flux or illuminance ofthe first lighting element are thus especially due to the first lightingelement light generated by said first lighting element (during use).

One may also consider other applications, like over a bed or in a roomwith multiple beds. In such applications the illuminances may be chosendifferently, such as e.g. smaller and larger than 50 lux, respectively.

In general however, the illuminance at (first position p1, to be chosento be) 1 meter from the first lighting element will not be larger than50 lux. The maximum first lighting element illuminance (or luminousflux, see also below) may be due to the physical maximum intensity thelighting element can provide. It may however in other embodiments alsobe a value that is controlled by the control unit. Such value may bepreset (see also below). However, alternatively or additionally, asensor may be applied. Such sensor and control unit may then beconfigured to evaluate the illuminance at said first position. Thismight include a direct measurement or estimation. Especially, the firstposition may be a bed or part of a bed in a room. Hence, the maximumilluminance (or luminous flux) may be defined dependent upon thespecific application. Hence, especially 0.5≦d2≦5 m. In an embodiment,the first lighting element may (be configured to) have a maxiumilluminance at the first position (p1) within a first distance (d1) fromthe lighting element, with the first distance 0<d1≦15 m, especially0.5≦d2≦5 m, in the range of 20-100 lux, especially in the range of 40-60lux, such as 50 lux.

The first lighting element may comprise a single light source or aplurality of light sources. Especially, the first lighting elementcomprises one or more LED light sources. In a specific embodiment, thelight source comprises a solid state LED light source (such as a LED orlaser diode). The term “light source” may also relate to a plurality oflight sources, such as 2-20 (solid state) LED light sources. Hence, theterm LED may also refer to a plurality of LEDs. However, also more LEDsmay be applied in the first lighting element. Further, the term “firstlighting element” may also refer to a plurality of first light elements.The total luminous flux provided by such plurality of first lightingelements will be, as indicated above, especially be equal to or lowerthan 10,000 Lumen, more especially equal to or lower than 5,000 Lumen.Likewise, the total illuminance at position p1 due to the first lightingelement may especially be equal to or lower than 100 lux, especiallyequal to or lower than 50 lux (at position p1).

Especially, the first lighting element provides lighting element lightthat is blue deprived, i.e. for instance white light that has a colortemperature below 4000 K or light that is non-white due to a deficit ofblue light, especially due to a complete lack of blue light in thespectrum emitted by the element. The use of colored light may help toreduce a certain undesired biological response (like alerting people atnight).

The term white light herein, is known to the person skilled in the art.It especially relates to light having a correlated color temperature(CCT) between about 2000 and 20000 K, especially 2700-20000 K, forgeneral lighting especially in the range of about 2700 K and 6500 K, andfor backlighting purposes especially in the range of about 7000 K and20000 K, and especially within about 15 SDCM (standard deviation ofcolor matching) from the BBL (black body locus), especially within about10 SDCM from the BBL, even more especially within about 5 SDCM from theBBL.

The terms “violet light” or “violet emission” especially relates tolight having a wavelength in the range of about 380-440 nm. The terms“blue light” or “blue emission” especially relates to light having awavelength in the range of about 440-490 nm (including some violet andcyan hues). The terms “green light” or “green emission” especiallyrelate to light having a wavelength in the range of about 490-560 nm.The terms “yellow light” or “yellow emission” especially relate to lighthaving a wavelength in the range of about 540-570 nm. The terms “orangelight” or “orange emission” especially relate to light having awavelength in the range of about 570-600. The terms “red light” or “redemission” especially relate to light having a wavelength in the range ofabout 600-750 nm. The term “pink light” or “pink emission” refers tolight having a blue and a red component. The terms “visible”, “visiblelight” or “visible emission” refer to light having a wavelength in therange of about 380-750 nm.

The lighting element may further comprise the functionality to providedynamic properties to the light of the first lighting element. This willfurther be elucidated below.

The first lighting element may comprise a plurality of functionalities.

In embodiments, the control unit is especially configured to maintainthe first lighting element illuminance at said first position (p1)during a first predetermined period at a specific (variable) intensity,especially at an illuminance value larger than zero, when a generallighting illuminance level at said first position (p1) is below apredetermined first threshold level.

This functionality (b) may assure that when the general lighting levelis below a specific value (including zero), the first lighting elementprovides light. This can also be considered a “night light” or “dimlight” functionality.

In a specific embodiment, the predetermined first threshold level (atthe same first position) of the general lighting illuminance is 100 luxor smaller, especially 50 lux or smaller, or even 10 lux or less, suchas 5 lux or less. If larger than 50 lux, the lighting system may be usedin rooms wherein it may be relatively light, such as during the day. Athreshold of 50 lux or lower may especially relevant during the night.The predetermined first threshold level may be larger than zero, but itsvalue may in embodiments be defined dependent upon the intendedapplication. Alternatively, in an embodiment the threshold is defined asa luminous flux threshold (of all other (artificial) light sources thanthe first lighting element) of 5,000 lumen or smaller, especially 500lumen or smaller, or even 100 lumen (or lower), as also indicated below.Note that the predetermined first lighting element maximimum luminousflux is especially 10,000 Lumen, even more especially 5,000 Lumen. Infurther embodiments, the predetermined first lighting element maximimumluminous flux may even be lower, such as 500 Lumen, like 100 Lumen.

This general illuminance level may refer in embodiments to anilluminance provided by one or more other lighting elements which arealso part of the system. In such embodiments, the control unit cancontrol the lighting intensity of the first lighting element as functionof the general illuminance level of the one or more other lightingelements. These one or more other lighting elements, when beingfunctionally included in the lighting system, are herein also indicatedas “second lighting element”. Based one or more of a (light) sensor, atime program, etc., the control unit can evaluate the status of thesecond lighting element, and based thereon control the first lightingelement. Note that when such general lighting is switched off, thegeneral lighting illuminance will be zero by (this) definition (asgeneral illuminance level may refer in embodiments to illuminanceprovided by one or more other lighting elements which are also part ofthe system).

Hence, in a specific embodiment, the lighting system further comprises asecond lighting element configured to provide second lighting elementlight; the general lighting illuminance may especially be defined as theilluminance at said first position (p1) provided by said second lightingelement light.

In yet a further embodiment the luminance in the room resulting from thefirst lighting element has a maximum value of 50 cd/m² and the secondlighting element achieves a maximum luminance value of 20,000 cd/m²within the room/space where the system is used.

In yet a further embodiment, the ratio of the maximum luminance of thefirst lighting element and the second lighting element is at least 1:10,such as at least 1:50, like at least 1:100. Further, the first lightingelement may also result in a (non-zero) minimum luminance (within theilluminated area) of at least 2 cd/m², especially a (non-zero) minimumluminous flux of at least 0.2 cd/m². Further, also the second lightingelement may also have a (non-zero) minimum luminance (within allilluminated areas), especially of at least 20 cd/m², especially a(non-zero) minimum luminous flux of at least 20 cd/m². When the (second)lighting element comprises a plurality of (second) lighting elements,the cumulated (maximum) luminous fluxes should especially comply with(one or more of) above definition(s). Likewise, when the (second)lighting element comprises a plurality of (second) lighting elements,the cumulated (maximum) illuminances should especially comply with (oneor more of) above definition(s). Alternatively or additionally, in yet afurther embodiment, the ratio of the maximum luminous fluxes of thefirst lighting element and the second lighting element is at least 1:10,such as at least 1:50, like at least 1:100. In case of 5,000 lumenmaximum luminous flux for the first lighting element and 100,000 lumenmaximum luminous flux for the second lighting element, the ratio is1:20.

The luminous flux or illuminance of the second lighting element are thusespecially due to the second lighting element light generated by saidsecond lighting element (during use).

The maximum luminous flux (or other maximum intensities) may be definedby the specifications of the lighting element and optionally also by thecontrol unit. Likewise, the maximum illuminance is defined by thespecifications of the lighting element and optionally also by thecontrol unit. For instance, optionally the first lighting element mayprovide enough intensity to provide an illuminance >100 lux (at thefirst position (p1)). However, the control unit may define thepredetermined first lighting element maximum illuminance to be 50 lux(see also above).

Further, in general the illuminance at 1 meter from the first lightingelement is at least 0.5 lux, especially at least 1 lux, especiallyduring one or more of the herein described first predetermined period,second period and third period. This lower (non-zero) level may be basedon the lighting element specifications, but may also be controlled bythe control unit.

In a yet another specific embodiment, the general lighting illuminanceis defined as the illuminance at said first position (p1) provided bylight of any lighting element except for said first lighting elementlight. Especially then, the lighting system may further comprises afirst sensor, wherein the control unit and said first sensor areconfigured to evaluate the general lighting illuminance at said firstposition (p1). In such embodiment, natural light may be included in thegeneral lighting illuminance, or when no other lighting elements areavailable except for the first lighting element, only natural light maybe included in the general lighting illuminance. As now the generallighting illuminance may include contribution of sources that are notpart of the lighting system, such as daylight or light from the moon,etc., the lighting system may especially also include such first sensor.The term “sensor” may also relate to a plurality of sensors.

Note that the illuminance of the first lighting element is notconsidered to contribute to the general lighting illuminance and thatlight of any other light source when part of the system and/or fromother light sources may be considered general lighting (see definitionsabove).

The (first) predetermined period can be a period that returns each day,and may be triggered by a time clock or digital time schedule, or bylight conditions that are sensed by a sensor, such as above indicatedfirst sensor. The first predetermined period can be triggered by amanual trigger. Hence, the control unit may include a (remote) userinterface functionally coupled to said control unit. The firstpredetermined period may thus embodiments be a fixed period, such as 8hours from 10 pm to 6 am, but may optionally also be a period thatdefined by a user. The first predetermined period may be the timebetween sunset and sunrise but the first predetermined period may alsobe the period that e.g. the general lighting illuminance level is below50 lux (or another threshold value) (see also below). In an embodiment,the functionality under b) is a default setting and the predeterminedperiod is (thus) 24 hours. This may imply that always when the generallighting illuminance level is below the first threshold level, such asswitched off, the first lighting element is switched on.

Anyhow, during said (first) predetermined period, the first lightingelement may at least be switched on when the following applies: (1a) asecond lighting element is comprised by the lighting system and saidsecond lighting element is switched off, (1b) a second lighting elementis comprised by the lighting system and said second lighting elementprovides second lighting element light (at said first position) belowthe threshold level, (2a) there is no further lighting element and thegeneral lighting level (at said first position) is below the thresholdlevel, (2b) a second lighting element is comprised by the lightingsystem and said second lighting element together with other lightsources (like daylight) provide light (at said first position) below thethreshold level. These options correspond to the above given definitionsof general lighting illuminance.

Especially, the first lighting element is configured to provide at least1 lux at the first position (during one or more of said first, secondand third periods). In dark rooms, this may already be enough to beperceived by a user. Hence, the b) part especially provides a nightlight functionality.

In case the general lighting illuminance is non-zero, one may inembodiments chose the level of illuminance of the first lightingelement. For instance, one may relate the illuminance of the firstlighting element to the general illuminance level. Hence, the controlunit may further especially be configured to maintain the first lightingelement illuminance at said first position (p1) during a secondpredetermined period at an illuminance value a*y*E when the generallighting illuminance level at said first position (p1) is y*E, y beingthe factor the general lighting illuminance is below E, with 0<y<1, andparameter a being a predetermined lighting setting with 0<a≦1/y. Thisparameter a can in embodiments be fixed, can be user selected, can betime dependent, etc.

Parameter a or (light) setting a may be fixed value or may be variablevalue. In embodiments it may also be that during a specific timeparameter a is fixed and during a period parameter a is variable.Especially when the general lighting illuminance drops, the firstlighting element (and optionally also the second lighting element whenbeing part of the lighting system and (also) having a controllable lightintensity) may be used to gradually decrease the overall illuminance andthereby prevent or reduce illuminance jumps.

Especially, the first lighting element may be used to gradually changethe overall illuminance (or luminous flux or luminance) during theperiod a person may desire to fall asleep or should fall asleep to alevel that may be comfortable during sleep. Further, especially thefirst lighting element may be used to gradually change the overallilluminance (or luminous flux or luminance) during the period a personmay desire to wake up or should fall wake up to a level that may becomfortable during a wake up period.

The control unit is especially configured to control the first lightingelement, even more especially its first lighting element light.Optionally, the control unit is further especially configured to controlthe second lighting element (when available), even more especially itssecond lighting element light. Hence, the control unit may inembodiments (e.g.) be configured to gradually decrease the firstlighting element illuminance (or luminous flux, or luminance) from afirst value to a second value. This may thus also imply that a graduallychanges with time. The functionality that the first lighting unit inembodiments may be configured to gradually decrease the first lightingelement illuminance (or luminous flux or luminance) from a first valueto a second value may optionally be independent whether there (still) isa non-zero general lighting illuminance (or luminous flux or luminance)or whether the latter is zero, such as when e.g. the second lightingelement would be switched off (and/or when all other light sources wouldbe off or shielded off (with e.g. blindings)). Hence, when the controlunit would be able to perceive that the general illuminance (or luminousflux or luminance) suddenly drops to zero, or would the control unit beable to product a zero general illuminance, then the control unit mayfurther be configured to control the first lighting unit to provide afirst lighting unit illuminance (or luminous flux or luminance) thatmatches as good as possible, together with the present generalilluminance (or luminous flux or luminance), a previous generalilluminance (or luminous flux or luminance) level. The control unit maythus be configured to delay changes in the general illuminance (orluminous flux or luminance) level and arrive with a delay at a desiredilluminance (or luminous flux or luminance) level of the first lightingelement. For instance, assume that the general lighting illuminancelevel is 200 lux or 50 lux, and assume that the predetermined maximumfirst lighting element illuminance (E) is 50 lux, and assume that thegeneral lighting illuminance level drops suddenly to 10 lux, the controlunit may control the first lighting illuminance level to 50 or 40 lux,respectively, to match as good as possible the general illuminanceduring the previous state. Subsequently, the control unit may graduallylower the illuminance of the first lighting element to a level of e.g.20 lux. Then a user may still perceive the first lighting element anddiscriminate it from the general lighting illuminance. In theseexamples, E=50 lux, y=0.2, and a is first 5 and 4, respectively, andafter a while the parameter a is 2. As the first lighting element cannotgive more illuminance than its maximum E, parameter a is related to y.

In yet a further embodiment, the control unit is configured to controlthe predetermined lighting setting a to a value n, when y≦1/n, with n=2.In such embodiments, the first lighting element, such as a night light,provides light at least twice the background (assuming that this isfeasible for the first lighting element, such as a night light).

Note that when a second lighting element is included in the system, thecontrol unit may in embodiments be configured to gradually decrease thefirst lighting element illuminance (or luminous flux or luminance) andthe second lighting element illuminance (or luminous flux or luminance)from a first value to a second value. In this way, even better a gradualdecrease may be obtained. Hence, when for instance during a nocturnalperiod a user switches off or on the light, the lighting system mayprevent a sudden jump in illuminance (or luminous flux or luminance) andprovide a gradual decrease or increase.

The second predetermined period can be a period that returns each day,and may be triggered by a time clock or digital time schedule, or bylight conditions that are sensed by a sensor, such as above indicatedsecond sensor. The second predetermined period can be triggered by amanual trigger. Hence, the control unit may include a (remote) userinterface functionally coupled to said control unit. The secondpredetermined period may thus embodiments be a fixed period, such as 8hours from 10 pm to 6 am, but may optionally also be a period thatdefined by a user. The second predetermined period may be the timebetween sunset and sunrise but the second predetermined period may alsobe the period that e.g. the general lighting illuminance level is below50 lux (or another threshold value). In an embodiment, the functionalityunder c) is a default setting and the predetermined period is (thus) 24hours. This may imply that always when the general lighting illuminancelevel is below the first threshold level, the first lighting element isswitched on.

In embodiments, the first predetermined period and second predeterminedperiod may be defined as a single predetermined period. The phrase“adapt during a predetermined period the first lighting element light toa general lighting level” and similar phrases may especially refer tothe above described first predetermined period and the secondpredetermined period.

As indicated above, in an embodiment the lighting system may furtherespecially be configured to provide during a third predetermined periodfirst lighting element light with a dynamic property, especiallyselected from the group of a moving or changing light pattern, a colorchange, and an intensity change. This dynamic property may especiallyfacilitate falling asleep during periods when one is awake but desiresto fall asleep or should fall asleep (including (undesired) nocturnalawakening). Hence, these dynamic effects are offered during a thirdpredetermined period. The phrase “provide during a further predeterminedperiod the first lighting element” and similar phrases may especiallyrefer to the above indicated third predetermined period.

Hence, in a further aspect the invention also provides a lighting systemcomprising a first lighting element and a control unit for controllingthe first lighting element to provide a first lighting element light,wherein the lighting system is configured to (a) adapt during a (firstand/or second) predetermined period the first lighting element light toa general lighting level, and (b) adapt during a (third or further)predetermined period the first lighting element light to comprises adynamic property selected from the group of moving or changing a lightpattern, changing a color, and changing an intensity of said firstlighting element light, even more especially to adapt during a (third orfurther) predetermined period the first lighting element light to adimmed lighting level wherein the dimmed lighting level furthercomprises a dynamic property selected from the group of moving orchanging a light pattern, changing a color, and changing an intensity ofsaid first lighting element light.

It is especially desired that the dynamics are not too slow (then theyare not perceived) but also not too fast. Especially, any change in theoptical properties of the first lighting element light selected frommoving the light pattern, a color change and an intensity change isespecially gradual. Hence, especially, the control unit is configured tocontrol a change in luminous flux at the light exit window at a specificwavelength is especially in the range of 0.1-5%/s, such as 0.5-4%/s.Alternatively or additionally, the control unit is (also) configured tocontrol a change in intensity at a predetermined wavelength of the firstlighting element light at any point in a plane of 1 m² perpendicular toa beam of light of first lighting element light at a second distance(d2) from the lighting element, with the second distance 0<d2≦15 m saidfirst position in the range of 0.1-5%/s, such as 0.5-4%/s, especiallywith 0.5≦d2≦5 m.

The third (or further) predetermined period can be a period that returnseach day, and may be triggered by a time clock or digital time schedule,or by light conditions that are sensed by a sensor, such as aboveindicated third sensor. The third predetermined period can be triggeredby a manual trigger. Hence, the control unit may include a (remote) userinterface functionally coupled to said control unit. The thirdpredetermined period may thus embodiments be a fixed period, such as 8hours from 10 pm to 6 am, but may optionally also be a period thatdefined by a user. The third predetermined period may be the timebetween sunset and sunrise but the third predetermined period may alsobe the period that e.g. the general lighting illuminance level is below50 lux (or another threshold value). In an embodiment, the functionalityunder d) is a default setting and the predetermined period is (thus) 24hours. This may imply that always when the general lighting illuminancelevel is below the first threshold level, the first lighting element isswitched on.

Especially, during the third (or further) period especially a pluralityof times one or more of the following sequentially takes place (i) amove of a light pattern, (ii) a change of a light pattern), (iii) acolor change of the light, and (iv) an intensity change of the light.Hence, for instance a sky with stars may be projected on a ceiling,wherein the a plurality of stars move (sequentially) over the ceiling.Or, for instance the color of the light may change from yellow to red anvice versa a plurality of times, etc. etc. Especially, those movesand/or changes occur gradually. Those moves and/or changes may accordinga predetermined sequence or random. Also a combination is possible, suchas a random order of a plurality of predetermined sequences.

In embodiments, the (first) predetermined period and third (or further)predetermined period may be defined as a single predetermined period. Inembodiments, the second predetermined period and third predeterminedperiod may be defined as a single predetermined period. In embodiments,the first predetermined period, the second predetermined period andthird predetermined period may be defined as a single predeterminedperiod. Hence, in a specific embodiment the first predetermined period,the second predetermined period and the third predetermined periodcoincide.

In yet a further embodiment, wherein the first predetermined period, thesecond predetermined period and the third predetermined period start ata time selected from one or more ranges of 12 am-3 pm and 7 pm-11 pm. Inanother further embodiment, the lighting system further comprises asecond sensor configured to sense nocturnal activity of a human, andwherein the control unit is configured to start providing first lightingelement light with the dynamic property when nocturnal activity is abovea predetermined nocturnal activity threshold value. Such sensor may e.g.include a motion sensor. It may also include a sensor that evaluates thetype and/or depths of sleeping.

During the period that dynamic light effects are created, in embodimentsalso (dim) light may be provided that has a constant intensity. Hence,the lighting system, such as in an embodiment especially the lightingelement, may be configured to provide during at least part of the(third) predetermined period first lighting element light with a dynamicproperty and second lighting element light having a static property(i.e. especially having constant intensity; even more especially color,color temperature and intensity are kept constant). In a furtherembodiment, to obtain these effects the lighting system may include asecond lighting element (configured to provide second lighting elementlight).

As already indicated above, there is a relation between the luminousflux and the illuminance. The illuminances identified herein areespecially relevant for the herein used first position (p1). This firstposition may especially be close to a bed, such as close to a pillow ona bed. Hence, the lighting system (and method; see below) may optionallybe defined in terms of luminous fluxes.

Hence, in yet a further aspect, the invention also provides a lightingsystem comprising a first lighting element, an optional second lightingelement, an optional first sensor, and a control unit, wherein: a) thefirst lighting element is configured to provide first lighting elementlight with controllable first lighting element luminous flux, whereinthe lighting element luminous flux can be selected from a plurality ofvalues in the range of 0-Φ, with Φ being a predetermined first lightingelement maximum luminous flux, wherein the first lighting elementmaximum luminous flux is especially 10,000 Lumen, even more especiallyespecially 5,000 Lumen; wherein the optional second lighting element isconfigured to provide second lighting element light with (optionallycontrollable) second lighting element luminous flux, and whereinespecially the optional second lighting element has a maximum luminousflux of 100,000 Lumen; and wherein optionally the control unit and saidoptional first sensor are configured to evaluate a general lightingluminous flux; b) the control unit is especially configured to maintaina first lighting element luminous flux of the first lighting element,during a first predetermined period at a luminous flux value larger thanzero when a (the) general lighting luminous flux level is below apredetermined first luminous flux threshold level, with thepredetermined first luminous flux threshold level especially being 5,000Lumen, especially being 500 Lumen, even more especially being 100 Lumen,such as 50 Lumen; c) the control unit is further especially configuredto maintain the first lighting element luminous flux during a secondpredetermined period at a luminous flux value a*y*Φ when the generallighting luminous flux is y*Φ, y being the factor the general lightingluminous flux is below Φ, with 0<y<1, the parameter a being apredetermined lighting setting with 0<a≦1/y, (and with Φ being thepredetermined first lighting element maximum luminous flux); and d) thelighting system is further especially configured to provide during athird predetermined period first lighting element light with a dynamicproperty especially selected from the group of a moving or changinglight pattern, a color change, and an intensity change, wherein duringthe third period especially a plurality of times one or more of thefollowing sequentially takes place (i) a move of a light pattern, (ii) achange of a light pattern), (iii) a color change of the light, and (iv)an intensity change of the light.

Hence, in yet a further aspect, the invention also provides a lightingsystem comprising a first lighting element and a control unit, wherein:a) the first lighting element is configured to provide first lightingelement light with controllable lighting intensity, wherein the firstlighting intensity can be selected from a plurality of values in therange of 0-I, with I being a predetermined first lighting elementmaximum intensity; b) the control unit is configured to maintain a firstlighting element intensity during a first predetermined period at anintensity value larger than zero when a general lighting intensity isbelow a predetermined first threshold level; c) the control unit isfurther configured to maintain the first lighting element intensityduring a second predetermined period at an intensity value a*y*I whenthe general lighting intensity level is y*I, y being the factor thegeneral lighting intensity is below I, with 0<y<1, the parameter a beinga predetermined lighting setting with 0<a≦1/y, (and with I being apredetermined first lighting element maximum intensity, see also above);and d) the lighting system is further configured to provide during athird predetermined period first lighting element light with a dynamicproperty selected from the group of a moving or changing light pattern,a color change, and an intensity change, wherein during the third perioda plurality of times one or more of the following sequentially takesplace (i) a move of a light pattern, (ii) a change of a light pattern),(iii) a color change of the light, and (iv) an intensity change of thelight. For I for instance the luminous flux or the illuminance may bechosen.

Functionality (b) is especially relevant when the general lightingintensity is substantially zero, such as ≦⅕ of the predetermined firstlighting element maximum intensity (which may optionally also be definedas predetermined first lighting element maximum illuminance orpredetermined first lighting element maximum luminous flux), or whenthis intensity is zero (such as all artificial light sources switchedoff (except for the first lighting element). Functionality (c) isespecially relevant when general lighting intensity is not zero, butrelatively low, i.e. especially when the general lighting intensity isequal to or lower than the predetermined first lighting element maximumintensity. Again, these intensities may optionally be defined asilluminances or luminous fluxes.

Hence, for instance when the threshold value is 10 lux or 100 lumen (seeabove), the first lighting element may be switched on when the generalilluminance or luminous flux, respectively, is below said thresholdvalue, during a predetermined first period, which may optionally bedependent upon on the general illuminance or luminous flux,respectively. For instance, at the same time, dynamics may be providedto the light for a predetermined third period. When for instance thegeneral illuminance or luminous flux, respectively, is between 10-50lux, or between 100-5,000 lumen, respectively, the first lightingelement may also be switched on (during the second predeterminedperiod), and optionally scale the illuminance or luminous flux,respectively, of the first lighting element. During this period, orduring part of this period, also dynamics may be provided to the light(for a predetermined third period).

As indicated above, in yet a further aspect, the invention also providesa method for controlling lighting in a room using a lighting system,especially as defined herein, the lighting system comprising a lightingelement and a control unit, wherein the lighting element is configuredto provide first lighting element light with controllable intensity,especially with controllable lighting element luminous flux, wherein thecontrollable intensity, especially the (controllable) lighting elementluminous flux can be selected from a plurality of values in the range of0-Φ, with Φ being a predetermined first lighting element maximumluminous flux, the method comprising:

maintaining the first lighting element illuminance at said firstposition (p1) especially at a first position (p1) within a firstdistance (d1) from the lighting element, with the first distance isespecially 0<d1≦15 m, during a first predetermined period at a specific(variable) intensity, especially at an illuminance value larger thanzero when a general lighting illuminance level at said first position(p1) is below a predetermined first threshold level;

maintaining the first lighting element illuminance at said firstposition (p1) during a second predetermined period especially at anilluminance value a*y*E when the general lighting illuminance level atsaid first position (p1) is y*E, y being the factor the general lightingilluminance is below E, with 0<y<1, a especially being a predeterminedlighting setting with 0<a≦1/y, and with E being the predetermined firstlighting element maximum illuminance at said first position (p1); and

providing during a third predetermined period in a specific embodimentfirst lighting element light with a dynamic property, especiallyselected from the group of a moving or a changing of a light pattern, acolor change, and an intensity change, wherein especially during thethird period a plurality of times one or more of the followingsequentially takes place (i) the moving of the light pattern, (ii) thechanging of the light pattern), (iii) the color change of the embodimentfirst lighting element light, and (iv) the intensity change of theembodiment first lighting element light.

In yet a (more general) aspect, the invention provides also a method forcontrolling lighting in a room using a lighting system comprising alighting element and a control unit, the method comprising adaptingduring a predetermined period first lighting element light of the firstlighting element to a general lighting level, and providing during apredetermined period first lighting element light with a dynamicproperty selected from the group of a moving or a changing of a lightpattern, a color change, and an intensity change, wherein during saidperiod a plurality of times one or more of the following sequentiallytakes place (i) the moving of the light pattern, (ii) the changing ofthe light pattern), (iii) the color change of the first lighting elementlight, and (iv) the intensity change of the first lighting elementlight.

In a specific embodiment (of said method), said first position (p1) iswithin 1 meter from a bed, and wherein the method comprises starting thefirst predetermined period, the second predetermined period and thethird predetermined period at a time selected from the range 7 pm-11 pm.

As indicated above, the system and/or method may be used to facilitateafter nocturnal activity to fall asleep. Hence, the method may alsoinclude providing first lighting element light with the dynamic propertywhen nocturnal activity is above a predetermined nocturnal activitythreshold value. As too fast or to slow changes in the dynamics are notdesired, the method may further comprise controlling a change inintensity at a predetermined wavelength of the first lighting elementlight at said first position in the range of 0.1-5%/s.

As indicated above, the lighting system may further comprise a secondlighting element configured to provide second lighting element light.Hence, the method may further include controlling the intensity of thefirst lighting element light in relation to the intensity of the secondlighting element light.

As already indicated above, there is a relation between the luminousflux and the illuminance. Hence, also the method may be defined in termsof luminous fluxes. Hence, in a further aspect the invention alsoprovides a method for controlling lighting in a room using a lightingsystem, especially as defined in any one of the preceding claims, thelighting system comprising a lighting element, an optional first sensor,and a control unit, wherein (a) the lighting element is configured toprovide first lighting element light with controllable first lightingelement luminous flux, wherein the lighting element luminous flux can beselected from a plurality of values in the range of 0-Φ, with Φ being apredetermined first lighting element maximum luminous flux, wherein thefirst lighting element maximum luminous flux is especially 10,000 Lumen,even more especially especially 5,000 Lumen, wherein the optional secondlighting element is configured to provide second lighting element lightwith (optionally controllable) second lighting element luminous flux,and wherein especially the optional second lighting element has amaximum luminous flux of 100,000 Lumen; and wherein optionally thecontrol unit and said optional first sensor are configured to evaluate ageneral lighting luminous flux; the method comprising: (b) maintaining afirst lighting element luminous flux during a first predetermined periodat an luminous flux value larger than zero when a general lightingluminous flux level is below a predetermined first luminous fluxthreshold level; (c) maintaining the first lighting element luminousflux during a second predetermined period at an illuminance value a*y*Φwhen the general lighting luminous flux level at said first position(p1) is y*Φ, y being the factor the general lighting luminous flux isbelow Φ, with 0<y<1, parameter a being a predetermined lighting settingwith 0<a≦1/y; and (d) providing during a third predetermined periodfirst lighting element light with a dynamic property selected from thegroup of a moving or changing light pattern, a color change, and anintensity change, wherein during the third period a plurality of timesone or more of the following sequentially takes place (i) a move of alight pattern, (ii) a change of a light pattern), (iii) a color changeof the light, and (iv) an intensity change of the light.

The invention further provides a computer program product, when run acomputer configured to control a lighting system, especially as definedherein, according to the method as defined herein. Hence, the inventionalso provides a computer program product, when when running on acomputer, is configured to perform the herein described method,especially control a lighting system according to such method.

Herein, the term “light intensity” may refer to one or more of luminousintensity and illuminance. Further, the phrase “included in the system”and similar phrases indicate that the described item is functionallycoupled to the system.

The term “substantially” herein, such as in “substantially all light” orin “substantially consists”, will be understood by the person skilled inthe art. The term “substantially” may also include embodiments with“entirely”, “completely”, “all”, etc. Hence, in embodiments theadjective substantially may also be removed. Where applicable, the term“substantially” may also relate to 90% or higher, such as 95% or higher,especially 99% or higher, even more especially 99.5% or higher,including 100%. The term “comprise” includes also embodiments whereinthe term “comprises” means “consists of”. The term “and/or” especiallyrelates to one or more of the items mentioned before and after “and/or”.For instance, a phrase “item 1 and/or item 2” and similar phrases mayrelate to one or more of item 1 and item 2. The term “comprising” may inan embodiment refer to “consisting of” but may in another embodimentalso refer to “containing at least the defined species and optionallyone or more other species”.

Furthermore, the terms first, second, third and the like (such as“further” in “further predetermined period”) in the description and inthe claims, are used for distinguishing between similar elements and notnecessarily for describing a sequential or chronological order. It is tobe understood that the terms so used are interchangeable underappropriate circumstances and that the embodiments of the inventiondescribed herein are capable of operation in other sequences thandescribed or illustrated herein.

The devices herein are amongst others described during operation. Aswill be clear to the person skilled in the art, the invention is notlimited to methods of operation or devices in operation.

It should be noted that the above-mentioned embodiments illustraterather than limit the invention, and that those skilled in the art willbe able to design many alternative embodiments without departing fromthe scope of the appended claims. In the claims, any reference signsplaced between parentheses shall not be construed as limiting the claim.Use of the verb “to comprise” and its conjugations does not exclude thepresence of elements or steps other than those stated in a claim. Thearticle “a” or “an” preceding an element does not exclude the presenceof a plurality of such elements. The invention may be implemented bymeans of hardware comprising several distinct elements, and by means ofa suitably programmed computer. In the device claim enumerating severalmeans, several of these means may be embodied by one and the same itemof hardware. The mere fact that certain measures are recited in mutuallydifferent dependent claims does not indicate that a combination of thesemeasures cannot be used to advantage.

A computer program may be stored/distributed on a suitablenon-transitory storage medium, such as an optical storage medium or asolid-state medium supplied together with or as part of other hardware,but may also be distributed in other forms, such as via the Internet orother wired or wireless telecommunication systems.

The invention further applies to a device comprising one or more of thecharacterizing features described in the description and/or shown in theattached drawings. The invention further pertains to a method or processcomprising one or more of the characterizing features described in thedescription and/or shown in the attached drawings.

The various aspects discussed in this patent can be combined in order toprovide additional advantages. Furthermore, some of the features canform the basis for one or more divisional applications.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of exampleonly, with reference to the accompanying schematic drawings in whichcorresponding reference symbols indicate corresponding parts, and inwhich:

FIG. 1 schematically depicts an application of the system;

FIGS. 2a-2d schematically depict some aspects of the invention; and

FIG. 3 schematically depicts an application of the system.

The drawings are not necessarily on scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 schematically depicts a lighting system 100 comprising a firstlighting element 10 and a control unit 50. The first lighting element 10is configured to provide first lighting element light 11 withcontrollable first lighting element illuminance. A first position p1 isindicated, at which the illuminance may be evaluated. This firstposition p1 is within a first distance d1 from the lighting element 10,with the first distance 0<d1≦15 m.

The first lighting element has a light exit window 13. Further, thelighting system may be further configured to provide first lightingelement light (11) with a dynamic property selected from the group of amoving or changing light pattern, a color change, and an intensitychange. To this end, the lighting element may comprise a plurality oflight sources, with reference indicated one or more light sources,and/or a display element, such as a moving element with a transparent(colored) piece or an LCD element. Other options are also possible todisplay colors or light patters on a wall and/or ceiling or otherelement which receives light 11 from the first lighting element.Reference 1030 indicates e.g. a wall in a room 1000.

Reference 20 indicates an optional second lighting element, also havinga light exit window, indicated with reference 23. The 2^(nd) lightingelement is configured to provide second lighting element light 21. Thecontrol unit 50 may be configured to control also such optional 2^(nd)lighting element 20.

Reference 16 indicates a virtual plane at a distance d2 from the firstlighting element 10, perpendicular to a ray 11 b of beam 11 a (seefurther also FIG. 2d ).

Instead of a projection on a wall 1030, the first lighting element 100may also project on the ceiling (not shown). Alternatively oradditionally, a first lighting element may be provided as lightingelement comprised by the ceiling. Hence, a pattern on a light exitwindow may be perceived by a person below the first lighting element(not shown).

FIG. 2a very schematically shows with curve I a possible progress ofgeneral lighting over a period of 24 hours, which may also includes acontribution of a second lighting element (or other source ofnon-natural light). Curve II indicates the deviation of such curve whensuddenly the second lighting element is switched off and/or when e.g.blindings are closed. Curve III shows how the lighting system maycompensate a too fast change in the general lighting illuminance. Inthis way, the first lighting element light arrives after some time at alevel, especially higher than a background level, still perceivable by aperson. Such level may be maintained during the night, see curve IV.

FIG. 2b schematically depicts an embodiment when e.g. a sensor sensesnocturnal activity at time T1. At such moment, the first lightingelement light (and also optionally light of the second lighten element,when available) may be increased to a certain amount, but to “normal”levels as during the day (indicated with 100%). When at T2 the sensorperceives that the person starts to fall asleep again and/or enters abed, the level may decrease again.

FIG. 2c very schematically depicts a dynamical effect, such as a moving(and optionally fading) star on a wall 1030. Of course, all kind ofdynamic effects are possible. Further, note that the first lightingelement may be used in a projection mode and/or in a direct mode. Forinstance, the first lighting element may also be a light tile on a wallor ceiling which may be perceived directly. Hence, in an embodiment FIG.2c may also schematically depict a ceiling or a part of a ceiling with afirst lighting element (in operation).

FIG. 2d schematically depicts virtual plane 16. This plane is used todefine in a way the minimum and maximum change in intensity. At eachpoint in the plane, the intensity at a specific wavelength shouldpreferably change in a range of 01.-5%/s. Referring to FIG. 1, thecontrol unit 50 is configured to control a change in intensity at apredetermined wavelength of the first lighting element light 11 at anypoint in a plane 16 of 1 m² perpendicular to a beam of light 11 of firstlighting element light 11 at a second distance d2 from the lightingelement 10, with the second distance 0<d2≦15 m said first position inthe range of 0.1-5%/s.

FIG. 3 schematically depicts a further application, e.g. in a bedroom orhospital room 1000.

The illuminance levels of the dynamic dim light effect are especiallylow, preferably less than 30 lux, or even better <10 lux. Thisfacilitates a rapid sleep onset (no melatonin suppression), but alsoallows for a gradual wake up. Moreover during nocturnal awakenings thedynamic dim light effect will help to ease returning to sleep and reducenocturnal restlessness.

In order to facilitate unwinding and relaxation some, or all, of the(il)luminated areas of the dim light effect are dynamic in nature. Thedynamics can be in the (1) intensity of the dim light effect that isgradually changing, for instance producing light intensity changes thatmimic a glowing fireplace; (2) changing spectral composition: forinstance moving from orange to red to yellow with some pattern overtime, or a color change along the blackbody line, optionally incombination with 1; (3) changing the location of the illuminated areas:(a) Gradually: like when projecting through a rotating slide with somepatterns/figures on it. (b) abruptly: for instance by a large areapixelated light source; and (4) any combination of two or three of(1)-(3).

The preferred dynamics has in an embodiment a cycle time of 1 to 120seconds, preferably 2-10 seconds if the dynamics is a glowing effect.However, larger cycle times are also possible (see above). Further, asindicated above, a random generation of the dynamics is also possible

In an embodiment, projection can be used to generate a dynamic dim lighteffect. Alternatively, different types of light patterns can be createdwith a ceiling containing a pixilated distribution of LED point sources.In general, glowing light effects are created with sinusoidal variationof light output. Preferably, the dynamic dim light effects are offeredin the bedtime period, either during the full bed period, or only whilefalling asleep and/or waking up. The dim light dynamic effects duringthe bedtime period need not remain identical. Different effects can beused during different parts of the bedtime period: (A) while fallingasleep (f.i. using yellow or red light effects, to unwind with lighteffects that do not suppress the sleep promoting hormone melatonin); (B)while maintaining sleep (f.i. a starry sky appearance with LEDs placedover the ceiling area); (C) while waking up (f.i. adding a rising suneffect by means of a wall washer to the starry sky, gradually enhancingboth brightness and the blue light content, to wake people up moreeffectively). Another option can be to create a bright light conditionin the morning with on/off dynamics that result in flicker/flashes thatact as an alarm clock to wake people more efficiently/rapidly after anight's sleep.

The system can be connected to the biofeedback signals from a camera,Actiwatch, IPhone sleep App, motion sensors, sound. Upon detection of abiofeedback signal above a threshold, and a time signal one of the abovelight effects is created.

In an embodiment, general lighting created with a pixilated ceilingluminaire, preferably embodied in ceiling tiles, covering the wholeceiling in the area where beds are present, can be provided.

In another embodiment, at first the “starry sky” simulation can be used:the individual LED points glow in random order. Here, glowing may meanthat the light output varies between two levels of light output, in acyclic manner, possibly with a color temperature change as well (morereddish light (low color temperature) at minimum light level) and morebluish light (high color temperature) at high maximum light output).“Random order” may mean that the phases of the dimming cycle for thedifferent light points are different according a random distribution. Toobtain the warm dimming behavior a red LED is mixed with cool whiteLEDs. To obtain the starry sky effect, the light output of each LEDpoint is in a different phase of the cyclic repetition of the glowingbehavior. To make the starry sky even more realistic, some LED pointshave a higher light level compared with other, in this way for instancethe “Great Bear” sign can be simulated. These signs can be changeddepending on the time of the year, thus the light effect is coupled to ayear-clock. In a further embodiment, the use of tunable parameters maybe important to provide customization of the light effect to individualuser needs: (a) the difference in light output between the minimum andmaximum light level as well as the minimum light level can be fine tunedby the user via the user interface; and/or (b) the speed of the dynamiclight change (=dimming cycle time) can be fine tuned by the user via theuser interface. Since the intention is to have a relaxing nocturnallight effect, moderate to slow speed of the cyclic behavior is required(one cycle with variable dimming per light point takes at least 2seconds or more).

In another embodiment, artistic dynamic patterns (e.g. moving waves orwater rippling) can be used, that can be set to a glowing mode as well.Again, the difference in light output between the minimum and maximumlight level, the minimum light level and the speed of the dynamic lightchange can be fine tuned by the user via the user interface.

In the morning, the ceiling creates bright light just before wakeup time(the wake-up light effect). With presence detection above the beds,light can be switched on in local areas only, in case more than one bedis present in the same space.

Application may e.g. in Neonatal Intensive Care Units, bedrooms in carefacilities for demented elderly, in hospital patient rooms on pediatricor geriatric wards, in hotels, in baby bedrooms, in bedroom lightingsystems for homes, etc.

The invention claimed is:
 1. A lighting system comprising a firstlighting element and a control unit for controlling the first lightingelement to provide a first lighting element light, wherein the lightingsystem is configured to: provide during a predetermined period the firstlighting element light to a first lighting level, and provide during afurther predetermined period the first lighting element light to asecond or dimmed light level or condition wherein the dimmed lightcondition further comprises a dynamic property selected from the groupof moving or changing a light pattern, changing a color, and cyclicvarying an intensity of said first lighting element light, the firstlighting element is configured to provide first lighting element lightwith a controllable lighting element luminous flux, wherein the lightingelement luminous flux is being selected from a plurality of values inthe range of 0-φ, with φ being a predetermined first lighting elementmaximum luminous flux; the control unit is configured to maintain afirst lighting element illuminance at a first position (p1) within afirst distance (d1) from the lighting element, with the first distance0<d1≦15 m, during a first predetermined period at an illuminance valuelarger than zero when a general lighting illuminance level at said firstposition (p1) is below a predetermined first threshold level; thecontrol unit is further configured to maintain the first lightingelement illuminance at said first position (p1) during a secondpredetermined period at an illuminance value a*y*E when the generallighting illuminance level at said first position (p1) is y*E, y beingthe factor the general lighting illuminance is below E, with 0<y<1, theparameter being a predetermined lighting setting with 0<a≦1/y, and withE being a predetermined first lighting element maximum illuminance atsaid first position (p1); and the lighting system is further configuredto provide during a third predetermined period first lighting elementlight with said dynamic property selected from the group of a moving ora changing of a light pattern, a color change, and an intensity change,wherein during the third period a plurality of times one or more of thefollowing sequentially takes place (i) the moving of the light pattern,(ii) the changing of the light pattern), (iii) the color change of thefirst lighting element light, and (iv) the intensity change of the firstlighting element light.
 2. The lighting system according to claim 1,wherein the predetermined first threshold level of the general lightingilluminance is 50 lux or smaller, wherein the predetermined firstlighting element maximum illuminance is 50 lux, and wherein the firstlighting element has a predetermined first lighting element maximumluminous flux (φ) of 5,000 Lumen.
 3. The lighting system according toclaim 1, further comprising a second lighting element configured toprovide second lighting element light, wherein the general lightingilluminance is defined as the illuminance at said first position (p1)provided by said second lighting element light, wherein the firstlighting element has a maximum luminous flux of 5,000 Lumen and whereinthe second lighting element has maximum luminous flux of 100,000 Lumen.4. The lighting system according to claim 1, wherein the generallighting illuminance is defined as the illuminance at said firstposition (p1) provided by light of any lighting element except for saidfirst lighting element light, wherein the lighting system furthercomprises a first sensor, and wherein the control unit and said firstsensor are configured to evaluate the general lighting illuminance atsaid first position (p1).
 5. The lighting system according to claim 1,wherein the control unit is configured to control the predeterminedlighting setting a to a value n, when y≦1/n, with n=2, and wherein thefirst predetermined period, the second predetermined period and thethird predetermined period coincide.
 6. The lighting system according toclaim 1, wherein the control unit is configured to gradually decreasethe first lighting element illuminance from a first value to a secondvalue.
 7. The lighting system according to claim 1, wherein the controlunit is configured to control a change in intensity at a predeterminedwavelength of the first lighting element light at any point in a planeof 1 m² perpendicular to a beam of light of first lighting element lightat a second distance (d2) from the lighting element, with the seconddistance 0<d2≦15 m said first position in the range of 0.1-5%/s.
 8. Thelighting system according to claim 1, wherein the first predeterminedperiod, the second predetermined period and the third predeterminedperiod start at a time selected from one or more ranges of 12 am-3 pmand 7 pm-11 pm, the lighting system further comprising a second sensorconfigured to sense nocturnal activity of a human, and wherein thecontrol unit is configured to start providing first lighting elementlight with the dynamic property when nocutural activity is above apredetermined nocturnal activity threshold value.
 9. A method forcontrolling lighting in a room using a lighting system comprising alighting element and a control unit, wherein the lighting element isconfigured to provide first lighting element light with controllablefirst lighting element luminous flux, wherein the lighting elementluminous flux is being selected from a plurality of values in the rangeof 0-φ, with φ being a predetermined lighting element maximum luminousflux, the method comprising: providing during a predetermined periodfirst lighting element light of the first lighting element (10) to afirst lighting level, providing during a further predetermined periodfirst lighting element light to a second or dimmed light level orcondition wherein the dimmed light condition further comprising adynamic property selected from the group of a moving or changing of alight pattern, changing a color change, and cyclic varying an intensity,maintaining a first lighting element illuminance at said first position(p1) within a first distance (d1) from the lighting element, with thefirst distance 0<d1≦15 m during a first predetermined period at anilluminance value larger than zero when a general lighting illuminancelevel at said first position (p1) is below a predetermined firstthreshold level; maintaining the first lighting element illuminance atsaid first position (p1) during a second predetermined period at anilluminance value a*y*E when the general lighting illuminance level atsaid first position (p1) is y*E, y being the factor the general lightingilluminance is below E, with 0<y<1, the parameter a being apredetermined lighting setting with 0<a≦1/y, and with E being apredetermined first lighting element maximum illuminance at said firstposition (p1); and providing during a third predetermined period firstlighting element light with a dynamic property selected from the groupof a moving or a changing of a light pattern, a color change, and anintensity change, wherein during the third period a plurality of timesone or more of the following sequentially takes place (i) the moving ofthe light pattern, (ii) the changing of the light pattern), (iii) thecolor change of the first lighting element light, and (iv) the intensitychange of the first lighting element light.
 10. The method according toclaim 9, wherein said first position (p1) is within 1 meter from a bed,and wherein the method comprises starting the first predeterminedperiod, the second predetermined period and the third predeterminedperiod at a time selected from the range 7 pm-11 pm, the method furthercomprising providing first lighting element light (11) with the dynamicproperty when nocutural activity is above a predetermined nocturalactivity threshold value.
 11. The method according to claim 9,comprising controlling a change in intensity at a predeterminedwavelength of the first lighting element light at said first position inthe range of 0.1-5%/s, and wherein the predetermined first thresholdlevel of the general lighting illuminance is 50 lux and wherein thefirst lighting element has a maximum luminous flux of 5,000 Lumen. 12.The method according to claim 9, wherein the lighting system furthercomprises a second lighting element configured to provide secondlighting element light, wherein the intensity of the first lightingelement light is controlled in relation to the intensity of the secondlighting element light, wherein the first lighting element has apredetermined first lighting element maximum luminous flux of 5,000Lumen and wherein the second lighting element has maximum luminous fluxof 100,000 Lumen.
 13. A computer program product, when run a computerconfigured to control a lighting system according to the method of claim9.